Page 15 - ScienceIndia Magazine March 2021
P. 15

         large ice mass, boulders, tree trunks and thick mud reached this confluence point, it was not able to turn towards Ta- povan area due to its high mo- mentum and took tangential path inside Rishi Ganga river. Itentered200m-300min- side the Rishi Ganga river and packed it, making an artificial lake on it. At this confluence point, the speed had gone down drastically, hence dust was not carried away further at the same speed but settled down maximally at mountain slopes near that confluence point.
Settlement of airburst dust near the confluence point of Rishi Ganga river and Raungti Nala
balanced, making them vul- nerable to disasters.
To avoid loss of lives and infrastructure, some impor- tant steps must be taken in this fragile Himalayan Re- gion such as identification of glacial lakes and hanging glacier, regular monitoring of discharge rates of all riv- ers, installation of automatic weather stations and Doppler radars all around the Himala- yas in proper density, and de- velopment and installation of acoustic sensors for monitor- ing of glacial crack propaga- tion. Such systems should be installed which can transmit data from satellites at Earth Receiving Stations.
Mountain weather fore- casting is a complex phenom- enon and this task must be top priority. Avalanche and landslide prediction and their mitigation in civil popula- tion region of Uttarakhand must be pushed. Advanced engineering methods must
be applied for construction of
 From here, glacial/melt
water took the front role
and moved forward, leav-
ing heavy mass behind at
Rishi Ganga-Raungti Nala confluence point. The wa-
ter moved forward towards
second confluence point of
Rishi Ganga-Dhauli Ganga,
travelling approximately 5.2
km surficial distance in steep downward slopes and fur-
ther eroded the soil of narrow
river banks, where more water
of Dhauli Ganga got added to the flow. At this confluence point, the Dhauli Ganga and Rishi Ganga rivers meet at low angle, thereby not affecting the flow of the former. This large water content then created the starting pulse of havoc towards Tapovan Power Project.
In the meantime, semi-circular confluence point played another role of open-air mixing machine, to churn the slurry of water and soil and throw it to- wards the Tapovan Project Area, behind the water flow pulse. The centrifugal force also acted in the compaction of embankment of artificial lake made on Rishi Ganga river — the embankment was made from inside by big chunks of rocks and boulder. The outer layer of embankment was made up of soil and small/ medium-sized rock-boulder com- posite. Prima facie, the embankment of artificial lake thus formed looks to be a highly compressed and stable structure,
Starting point of flash floods. Glacial avalanche, big rocky mountain dislocation and crack on rocks visible
90% of Uttarakhand is mountainous. Uncontrolled human activity on soft bed of rock leads to disasters when flash floods occur
but the possibly high ice mass constitu- ent makes it risky and unstable, with the rise in temperature in the warm months ahead.
Uttarakhand’s geography is very dynamic with 90% of the area being mountainous. Deforestation, land graz- ing, illegal development on the soft bed of rock lead to disasters when a flash flood hits the area. Experts are of view that while tampering with the Himala- yan slopes, one needs to be extra care- ful as these are the slopes, which have evolved by exogenic and endogenic processes and hence are dangerously
roads in the fragile Himalayan mountains rather than regularly used old methods. Big explosions/ blasts for road construction must be banned and controlled blast techniques must be used. Disaster management and ob- servation of river discharge and other important parameters must be made es- sential in school curriculum in the Hi-
malayan region. Each high Himalayan village must have a disaster management team, with required toolkit in case of an emergency. Large vertical construc- tions must be banned in high Himalayan ranges and only eco-friendly construc- tions be allowed. Last but not the least, internet facilities must be strengthened in the entire Himalayan region as social media played an important role in alert- ing the administration and evacuation of villagers this time.
*The writer is Technology Advisor to Secretary, Department of Defence (R&D) and to Chairman, DRDO
        Images Courtesy: Dr Sanjeev Kumar Joshi/ DRDO

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